Kawasaki was mainly involved in developing two cycle motorcycles. In the late sixties, Kawasaki intended to hit the market with an in-line-4-cylinder 4 stroke 750cc motorcycle. The displacement of the new model was set at 750cc and a mock up was completed in October 1968.In 1970, the Kawasaki changed their engine design policy so that the power band was not set near the engine's limit, thereby pursuing elegance and smooth engine performance. It is also note worthy that the main requirements for the Z1 engine were high speed, high stability, and ease of dealing with pollution problems. It has massive torque and a wide power band which makes it easy to manage. It combines high speed stability with low speed maneuverability and powerful disc/drum brakes ensure safe, predictable handling.The main features of the Z1 were the reliable double-cradle steel tube frame, a safe and reliable disc brake system, and ease of maintenance. Since the Z1 utilized the complicated DOHC mechanism, ease of maintenance was carefully considered at the design stage. As a result, the Z1 could be maintained without removing the engine from the body except for maintenance of crankshaft related parts.The Z1 style was achieved with tail-up mufflers, a light tear-drop formed fuel tank, and a slim, flowing seat. All the Z1 parts were individually examined and tested time after time resulting in a five year development period. Since the development stage, the Z1 was nicknamed "The New York Steak" and the Z1 was enthusiastically welcomed by markets as the "mouth watering motorcycle" when sales started. The retail price was $1,900 and the initial sales plan called for 1,500 vehicles per month including the European markets.In late 1972 the Z1 was introduced to the world and instantly became a best seller. Z1 went on sale in American in 1972 and Europe in 1973. The Kawasaki Z1 gave the world the first true super bike.